With the massive growth of the natural gas, shale-oil and fracking industries recently, many more workers are exposed to harmful levels of petrochemicals than ever before. While it may seem that workers are safe from chemical exposure, since petrochemicals are extracted from deep underground, they are actually in danger, because the chemicals, generally mixtures of hydrocarbon oils and gases, are brought to the surface under pressure, where they can expose workers who maintaining the equipment for separation, transport and storage. In the oil and gas industry wearable methane gas sensors are common, for detecting explosive or flammable level hazards, but no inexpensive technology exists that is light enough to be worn to protect workers from exposures, which are hazardous at concentrations much lower than their LEL. These types of customers require a low-cost alternative to its current expensive and labor intensive methods, namely collecting air samples and sending them to laboratories for analysis or using Drger tubes, which suffer for poor sensitivity and measurement difficulties. Seacoast Science, Inc. proposes to create a wearable personal exposure monitor for workers in any occupation where fuel contact is possible, such as the oil and gas industry, and airport (or fleet vehicle) workers, who are regularly exposed to fuel vapors and exhaust. The sensors are formed from chemically- responsive threads woven with flexible circuitry. The novelty of this product is that it can be made without a microchip substrat. This dosimeter/exposure monitor will combine low-cost components, to form a lightweight, disposable patch that can be worn outside of a worker's clothing, uniform, or hazmat suit. This research is a first step toward follow-on products, specifically smart-clothing and uniforms for protecting workers in the chemical-industry. Seacoast will take advantage of the electrically conductive nature of graphene and our long history of commercializing polymer-based sensors. The project's overall objectives are to (1) Select materials for the dosimeter array that can be used for selective and sensitive detection of chemicals indicative of fuel exposure, (2) Demonstrate low-cost volume manufacturing path using commercial micro-extrusion, (3) Determine effects of environmental and physical variables on the threads/arrays. By using flexible circuits, the system can be formed into a lightweight patch and worn by any industrial worker, similar to radiation dosimeters used by nuclear workers. The system can be linked to a GPS receiver, so that both the exposure and location can be tracked; information useful to find leaks in chemical processes, or to track plume movements over wide areas. Once developed, the product can be optimized for other markets where long-term worker or public health is a concern.